The goal is to conduct innovative, multidisciplinary research to identify the major sources of As and Hg exposure and to elucidate the protracted effects of early life exposure to As and Hg on human health. The ATSDR has identified As and Hg as the number one and number three environmental chemicals of concern with regard to human health. As exposure in the young increases the rates of diabetes, respiratory disease, and reproductive and developmental disorders. Methylmercury (MeHg) is a major contaminant in the food supply, particularly fish. For fetuses, infants, and children, exposure to MeHg has severe, adverse effects on the developing nervous system and interferes with cognitive thinking and memory. Despite growing concern and increasing research focus on As and Hg, there are significant knowledge gaps, especially with regard to very low levels of exposure in the US. Accordingly, the Dartmouth SRP is dedicated to obtaining new information on the effects of exposure to very low levels of As and Hg and thereby provide a foundation for science-based risk assessment leading to more informed, effective and comprehensive public health policies. The specific aims are to: (1) Elucidate how As is taken up and accumulated in rice and to use this information to identify new rice cultivars that assimilate lower amounts of arsenic; (2) Elucidate how MeHg accumulates in fish and how environmental changes in temperature, salinity, and carbon content influences MeHg in marine ecosystems; (3) Identify the dose dependent and relative effects of inorganic and organic As on the innate immune response of the lung to bacterial infections; and (4) Understand the effects of maternal and fetal As exposure on the development of metabolic syndrome and inflammation in mothers and newborns, the most at risk in our population. The research will be supported by a Training Core, a Trace Elements Analysis Core, and the Research Translation and Community Engagement Cores that will communicate our research findings to our stakeholders and communities, respectively.